The invention relates to a ventilation system providing NBC protection for at least one closed security space and/or protection space with constant slight excess pressure, which ventilation system substantially comprises an air inlet and air outlet, an explosion protection valve, a prefilter, a filter for suspended matter, an activated carbon filter and an air conveying device for sucking in the air to be purified and for distributing the purified air.
An air purification apparatus is known from WO 97/30755 A1, which comprises means for sucking in, purifying and distributing external air in at least one closed space, in particular in security and/or protection spaces. The apparatus is configured as an autonomous built-in unit with an air-tight housing, an air inlet connection piece for the air to be purified and an outlet connection piece. The housing surrounds a ventilator, at least one unused filter unit packed in an air-tight manner and an integrated bypass for the filter units. According to a special embodiment, two different filter units can be installed, which have different activated carbon filters. Depending on the damage position, one or other of the filter units can be used, both are immediately reachable at any time and fully functional. The purified air is blown constantly into the security and/or protection spaces, where with the generation of a lasting, slight excess pressure, it continuously escapes through leakages in the spaces and/or an excess pressure valve.
A filter unit is also known form DE 3841895 A1 which is preferably cylindrical and consists of individual filters which are nested together. In their totality, these individual filters ensure protection against atomic, biological and chemical toxic substances, in other words NBC protection. A ventilator which is flanged on externally is provided to operate the device. When the ventilation system is being fitted care has to be taken in a complex manner that all components are matched to one another both in terms of construction and also with regard to their functional characteristics.
During test runs of a ventilation system, which have to be carried out regularly, the functioning of all components involved and the adequate tightness of the security and/or protection spaces is checked. In the process, it must also be shown that a specified excess pressure in the space is constantly achieved during use.
Ventilation apparatuses are also known, for example from EP 0678693 B1, in which an explosion protection valve with a separately mounted prefilter is installed at the air inlet into the security and/or protection space. Furthermore, there are ventilation apparatuses, in which a prefilter is installed directly in the apparatus. The explosion protection valve is in turn arranged separately, it is installed without a prefilter in the security and/or protection space wall, or the explosion protection is dispensed with.